VLC (Visible Light Communication) synchronization algorithm based on zero-autocorrelation code pair
A visible light communication, zero autocorrelation technology, applied in the field of visible light communication, can solve the problems of system performance reduction and subsequent channel estimation algorithm efficiency reduction, etc., to achieve the effect of improving communication efficiency, low frequency offset estimation error, and improving performance
Inactive Publication Date: 2017-05-24
CENT SOUTH UNIV +1
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However, the OFDM system is very sensitive to symbol timing and carrier frequency offset. These two shortcomings will reduce the performance of the system and reduce the efficiency of subsequent channel estimation algorithms.
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[0018] Below in conjunction with accompanying drawing and example, the present invention is described in further detail.
[0019] The present invention proposes a timing synchronization and frequency offset estimation algorithm for a visible light communication system based on zero autocorrelation code pairs. The specific process is as follows figure 1 As shown, it includes the following three steps of S1, S2, and S3:
[0020] S1. Use figure 1 The mapping relationship shown and figure 2 The autocorrelation characteristics of the basic data are generated according to image 3 The structure generates synchronous symbols, and then adds the cyclic prefix to obtain the synchronous symbols of the OFDM system. After the peak-to-average power ratio reduction algorithm, the transmitter transmits the synchronous symbol data.
[0021] Zero autocorrelation code pair: sequence mapped by QAM Perform inverse Fourier transform to get the first part of the sequence ,according to , fo...
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The invention provides a timing synchronization and frequency offset estimation algorithm of a VLC system based on a zero-autocorrelation code pair, and relates to the technical field of VLC. The algorithm comprises the following steps that S1) a set parameter is mapped into the zero-autocorrelation code pair in the data transmitting end, the zero-autocorrelation code pair is combined to form synchronizing symbols according to a set structure, a cross cutting algorithm or u-law companding is selected, the peak-average power ratio of the synchronizing symbols is reduced, and an emitter emits compressed synchronizing symbol data; S2) received original data is calculated in a novel timing measuring method, and is compared with a dynamic threshold to obtain a timing moment and calculate a decimal frequency offset value; and S3) decimal frequency offset compensation is carried out on the received data, and the compensated data is calculated in an integer frequency offset estimation algorithm to obtain an integer frequency offset value. Compared with a zero-autocorrelation code based synchronizing algorithm, the algorithm of the invention is higher in the timing success rate and lower in low frequency offset estimation error, the peak-average power ratio of the synchronizing symbols is lower, and the algorithm is suitable for occasion with high requirement for the peak-average power ratio.
Description
technical field [0001] The invention relates to the technical field of visible light communication, and mainly relates to a universal zero-autocorrelation code pair and a novel synchronization and frequency offset estimation scheme based thereon. Background technique [0002] Visible light communication (visible light communication, VLC) is an optical communication technology that does not require the use of optical fibers. It combines the advantages of wireless communication and optical communication technologies to provide wireless, high-speed and reliable broadband access. VLC technology has a large potential available bandwidth, does not generate electromagnetic radiation, and is not easily affected by external electromagnetic interference. It can be widely used in special occasions that are sensitive to electromagnetic interference or even have no electromagnetic interference. VLC can use its indoor lighting source as a base station, combined with power line communicati...
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IPC IPC(8): H04L27/26
CPCH04L27/2614H04L27/2657H04L27/2662Y02D30/50
Inventor 钱学文邓宏贵王日初
Owner CENT SOUTH UNIV